Process for the production of hydrocinnamaldehyde



United States Patent ()fiice 3,372,199 Patented Mar. 5, 1968 3,372,199 PROCESS FOR THE PRODUCTION OF HYDROCINNAMALDEHYDE Paul N. Rylander, Newark, and Nathan Him'selstein, Hiilside, N..l., assignors to Engelhard Industries, Inc,

Newark, N.J., a corporation of Delaware No Drawing. Filed Mar. 20, 1964, Ser. No. 353,615 1 Claim. (Cl. 260-599) ABSTRACT OF THE DISCLOSURE Aryl aldehydes having alpha, beta olefinic bonds, such as cinnamaldehyde, are hydrogenated to the corresponding aralkyl aldehyde using palladium catalyst and an iron promoter. The method provides the desired aldehydes under appropriate conditions to the virtual exclusion of corresponding alcohols.

This invention relates to the production of hydrocinnamaldehyde and more particularly to a new and improved process for the hydrogenation of the alpha, beta olefinic bond of cinnamaldehyde and/or its substitution derivatives to produce the corresponding hydrocinnamaldehyde.

Palladium per se has been utilized heretofore as catalyst for the hydrogenation of the alpha, beta olefinic bond of cinnamaldehyde to the corresponding saturated aldehydes. However, the palladium is not entirely satisfactory for catalyzing such hydrogenation for the reason it does not have the desired selectivity to the saturated aldehyde, with material amounts of reaction by-products being formed due to hydrogenation of the carbonyl double bond as well as the olefinic bond. Further the hydrogenation rate with the palladium per se as catalyst has left room for improvement. When platinum black was utilized as catalyst, cinnamaldehyde was hydrogenated with difliculty and the product was primarily cinnamyl alcohol.

In accordance with the present invention, we have found that the alpha, beta olefinic bond of cinnamaldehyde and/ or its nuclear substitution derivatives is selectively hydrogenated to produce the corresponding hydrocinnamaldehyde and with a markedly higher selectivity to such saturated aldehyde than when using palladium per se as catalyst for the hydrogenation. Further the rate of hydrogenation of the cinnamaldehyde or substituted cinnarnaldehyde is increased considerably over that obtained with the palladium per se as catalyst. The process of this invention involves contacting the cinnamaldehyde and/ or its substitution derivative together with hydrogen with a palladium catalyst in the presence of an iron promoter. By reason of the palladium catalyst promoted with iron, there surprisingly and unexpectedly occurred a marked improvement in selectivity for the hydrogenation of the alpha, beta double bond with a spontaneous cessation of the reaction occurring after reaction of one molecular equivalent of H to produce the corresponding saturated aldehyde. However, when ferrous chloride was added to the platinum catalyst, the major product was cinnamyl alcohol. A selectivity to the desired saturated aldehyde as high as 100% has been achieved by the present invention, and an increase in the hydrogenation rate as much as 300% over that obtained by a supported palladium by itself as catalyst.

The iron promoter of this invention is an iron salt of an inorganic or organic acid, for instance ferrous or ferric salts of strong mineral acids, e.g. ferrous chloride, ferrous sulfate, ferric chloride, etc., or a ferrous salt of an organic acid, e.g. ferrous salts of organic dicarboxylic acids, for instance ferrous oxalate, ferrous salts of hydroxy dicarboxylic acids, for instance ferrous tartrate, and ferrous salts of organic monocarboxylic acids, for instance ferrous salts or lower alkanoic monocarboxylic acids, e.g. ferrous acetate and ferrous propionate. The iron promoter can be on a solid catalyst support together with the palladium also on the support, or can be added as such to the reaction mixture containing the cinnamaldehyde and/or its substitution derivative in liquid phase and also containing the palladium catalyst.

The palladium content of the supported catalyst may range, by weight, from about 0.5 %20%, preferably from about 2%l0% (based on weight of support plus palladium). The iron promoter, for instance ferrous chloride, is preferably present in amount of from about 0.5- 1.5 mols of such iron salt per mol of palladium. When the iron salt is supported on the carrier with the palladium, an aqueous solution of the iron salt is added to the solid supported palladium, followed by agitating the resulting mixture and then drying the product by heating same at a temperature not above 400 C., preferably between about 50 C. and 150 C. As exemplary, a catalyst of this invention was prepared by adding to 30 grams of a 5% palladium on carbon 70 ml. of a 0.2 M FeCl aqueous solution. The resulting suspension was stirred thoroughly and dried in an oven by being heated therein at C. for 24 hours. Alternatively instead of being substantially completely dried by means of the oven heating, the solids can be separated from the liquid, for instance by filtration, washed several times on the filter with the filtrate, and then only partially dried by drawing air through the catalyst on the filter, for instance for a period of 5-10 minutes.

Prior to the hydrogenation, the cinnamaldehyde and/ or its ring substitution derivative is preferably admixed with an organic liquid diluent which is inert to the hydrogenation, such as methanol.

The hydrogenation of this invention is illustrated by the following equation When cinnamaldehyde per se is the compound being hydrogenated and FeCl is the addi tive promoter for the Pd catalyst.

FeCla The hydrogen is preferably supplied to the reaction zone or chamber in a slight excess over the amount required to stoichiometrically react Withthe cinnamaldehyde to saturate its alpha, beta olefinic bond, typically a 5% excess of hydrogen.

Cinnamaldehydes which can be hydrogenated in accordance with the present invention include those of the formula wherein R and R are each from the group consisting of hydrogen, lower alkyl, i.e. 1-8 C alkyl, and lower alkoxy, i-.e. 1-8 C alkoxy; of the formula wherein A is lower alkylene, i.e. 1-3 C alkylene inclusive; and of the formula 2-methoXy-4-ethyl-hydrocinnamaldehyde with 2-methoXy-4-ethyl-cinnamaldehyde, 3,5-di1nethyl-hydrocinnamaldehyde with 3,5-dimethylcinnamaldehyde,

5 ,4-dietl1oXy-hydrocinnarnaldehyde with 2,4-diethoxycinnarnaldehyde, wherein A has the meaning stated supra, Z'mGthYIA'PHtYI'hYdrocinnamaldehyde With y Operating conditions for the hydrogenation of this in- 3 gbutyl'cmnamaldehydei vention are a temperature between room temperature and gugoxy'mrilethoxy'hyd'rocmnangaldehyde With about 100 (3., preferably room temperature. Pressures Q Y- l y utilized are between about atmospheric pressure and 0Hiethyl'hydfocmnamaldehyde h o-methylabout 1000 p.s.i.g. The hydrogenation can be carried out cmnamaldehyder either in continuous or batchwise operation. py y aldehyde with o-ethyl- Exemplary of cinnamaldehydes which can be hydrocmnamaldehyfie, u genated in accordance with this invention are cinnamalde- P I PY Y Wlth -p py hyde per se, Cmnamaldehyde, p methoxycinnamaldehyde o-butyl-hydrocinnamaldehyde with o-butyl- 3,4-methylenedioXy-cinnamaldehyde, fi i 2 3 methylenedioxy cinnamaldehyde p-met yl-hydrocinnamaldehyde with p-methyl- 2,3-ethylenedioxy-cinnamaldehyde, 2O cmnamaldehfidei L 3 4 eihylenedioxyiinnamaldehyde, p-ethyl-hydrocmnarnaldehyde with p-rnethyl- 3-ethoxy-4-methoxy-cinnamaldehyde, cmnamaldekiyde 2 meth0Xy 3 methyl cinnamaldehyde, p-ethyl-hydrocmnamaldehyde with p-ethyl- 2-methoxy-4-ethyl-cinnamaldehyde, i g g f h 3,5-dimethyl-cinnamaldehyde, yldrgcmnamalde Y Wlth p-p pyl- 2,4-diethoXy-cinnamaldehyde, Cmnama e y u 2 methy1 4 butyLcinnamaldehyde p-butyl-hydroclnnamaldehyde Wlth p-butyl- 3-butoxy-4-methoXy-cinnamaldehyde, i g q o methy1 cinnama1dehyde m-propy ydrocrnnamaldehyde wlth m-propylcrnnamaldehyde o-ethyl-cmnamaldehyde, h @PIOPYLcinnamaldehYde m-ethylydrocrnnamaldehyde with methylo-butyl-cinnamaldehyde, clingmaldehyd L p methy1 cinnama1dehyde, m-mvt yl hydrocmnamaldehyde With m-methylp-ethyl-cinnamaldehyde, (gnnamaldehyde ppmPYLcinl-mmaldehSIde mutyl-hydroclnnamaldehyde wlth m-butylp-butyl-cinnamaldehyde, g g gl y m-propyl-cinnamaldehyde, an S0 or fiffiggfi i ifigig ggg Test runs were carried out for the purpose f b t amaldeh g 40 paring the use of palladium as catalyst in the presence l g; y and absence of a ferrous salt of this invention, for cataan o lyzing the hydrogenation of cinnarnaldehyde t0 hydro- PrOduCt prod e 111 accordanc? with the Present cinnamaldehyde. The hydrogenation was carried out in process are hydrocmnarnaldehyde wlth hydrogenation of each run by first charging a mixture of 2 mL of clnnamaldehyde P Se, namaldehyde and 100 m1. of methanol as diluent, and p-methoxyhydrocinnamaldehyde with hydrogenation of also 200 mg. of 5% Pd on carbon (equivalent to about p-methoxy-cinnamaldehyde, .0001 mol Pd) to a hydrogenation reactor. For certain 3,4-methylenedioxyhydrocinnamaldehyde with 3,4- of the test runs ferrous chloride was added to the Pd rnethylenedioxymnn a y on carbon prior to its introduction into the reactor. The 23'methyleneelcxylydmcmnamaldehyde Wlth 5O reactor was placed in a shaker, the reactor evacuated of methyl n d ym gases and filled with H three times, and the shaker 'ii gf i i gfg g Wlth started. After the reaction stopped, the product was iden- 3 f i t iy fi gigfi gg de with 3 tified by infrared analysis. Cessation of the hydrogenation 3 ggg g f g y reaction was indicated by the level of the liquid in the 3 ethgxy 4methoxy hydminnan;a1dehyde with gas measuring burette rising to a certain level therein m /-4 h i ld h and then remaining stationary, i.e. not rising or lowering. 2.metho y-3-rnethy1-hydrocinnamaldehyde i h 2. The results of the test runs are set forth in the following methoxy-S-methyl-cinnamaldehyde, Table I:

TABLE I Time to total Total H3 absorbed Percent selectivity Additive to Pd/G Hz consumption (1111.) to hydroeinnamaldehyde 35 540 67 timi'fifoi neon- 12 410 100 0.0001 mol FeClz- 12 410 100 0.0001 mol F6612. 10 420 98 None 40 595 55 0.0001 mol FeOh- 20 485 81 0.00013 mol FeCh- 25 420 98 0.0001 mol Feon- 25 410 100 0.0001 mol F901,-

25 410 100 0.0001 mol F8011. 25 425 96 0.00011 m0lFeC1g 15 435 94 0.0001mol FeCh- 10 425 96 0.000111101FBC1z- 15 430 None 30 545 67 0.0G01IL101F9C12- 15 430 95 New a 222 Si The test results of Table I show the presence of the iron salt together with the supported palladium to be superior to the supported Pd alone for the hydrogenation of cinna-maldehyde to hydrocinnamaldehyde from the standpoint of a considerably improved hydrogenation rate, and also a considerably improved selectivity to the desired product. In Table I, the percent selectivity is determined in accordance with the following:

Selectivity:

Moles of Hydrocinnamaldehyde formed X 100 Moles Cinnamaldehyde reduced References Cited UNITED STATES PATENTS 2,875,131 2/1959 Carpenter et a1. 260599 X 2,976,321 3/1961 Dorsky et a1 260599 3,280,192

OTHER REFERENCES Shriner et al.: Jour. Amer. Chem, Soc., vol 46 (1924),

Tuley et al.: Jour. Amer. Chem. Soc, vol 47 (1925), pp. 3061-3068.

BERNARD HELFIN, Primary Examiner.

10/1966 Levy et al 260599 

